Changed conditions generally induce mere fluctuating variability, but sometimes they cause direct and definite effects; and these may become strongly marked in the course of time, though we have not sufficient evidence on this head.

变化的条件通常只引起波动的变化，但有时它们会引起直接和明确的影响；随着时间的推移，这些可能会变得很明显，尽管我们在这方面没有足够的证据。

There would indeed be force in Mr. Mivart's objection, if we were to attempt to account for the above resemblances, independently of natural selection, through mere fluctuating variability; but as the case stands there is none.

如果我们试图独立于自然选择， 仅通过波动的可变性来解释上述相似性， 那么 Mivart 先生的反对意见确实有说服力；但就目前情况而言， 没有。